Multi lumen inflatable cuff endotracheal (ET) tubes are well known in the medical arts particularly with respect to anesthesiology. Endotracheal tubes of this type will generally comprise a main lumen to maintain a patient's airway for the passage of respiratory gases to and from the lungs and a secondary lumen for inflation of the balloon cuff after the health care provider has intubated the patient. The inflatable cuff performs various functions including: securing a seal within a patient's tracheal, isolating the upper and lower trachea to prevent the deleterious passage of body fluids into the lungs, and permitting cyclic pressurization of a patient's lungs by a ventilator. U.S. Pat. No. 5,697,365, issued to Pell is typical of multi lumen inflatable cuff ET tubes in the art.
Inflatable cuff ET tubes may also include a tertiary lumen, for performing various functions. For example, U.S. Pat. No. 5,067,479, issued to Greear et al., discloses a tertiary lumen for suctioning bodily fluids from above the balloon cuff. U.S. Pat. No. 4,150,676, issued to Jackson, discloses an inflatable cuff ET tube which provides directional control over the tip of an ET tube by manipulation of a filament carried in a tertiary lumen. The directional control provided facilitates intubation of the device by an anesthetist or health care provider.
Another aspect related to the use of multi lumen ET tubes is proper insertion and positioning of the ET tube within the patient's trachea. U.S. Pat. No. 6,164,277, issued to Meredith, discloses the use of an audio guided intubation stylet to assist the practitioner with intubating “difficult” airways. Meredith discloses a stylet comprising a microphone that transmits breath sounds to an external speaker. By relying on the breath sounds, the practitioner can ensure intubation of the stylet into the trachea rather than the esophagus. The properly placed stylet is then used as guide tube for subsequent insertion of the ET tube. Once the ET tube is positioned, the stylet may then be removed. Merdeth also discusses the limitations of optically guided methods of intubation, citing their complexity, high cost, limited availability and limited usefulness when significant amounts of bodily fluids are present during intubation.
Multi lumen ET tubes have also been introduced which provide for the monitoring and management of critical physiological parameters. U.S. Pat. No. 5,937,858, issued to Connell, discloses a multi lumen ET tube in which tertiary lumina carry sampled gasses to external analyzers to determine respiratory gas concentrations. Similarly, U.S. Pat. No. 5,964,223, issued to Baran, discloses a nebulizing catheter for insertion into an ET tube for the delivery of medication in closer proximity to the lungs. Baran also discloses the use of removable catheters to carry sensors for monitoring various physiological parameters for nebulizer control and anesthetist monitoring. Accordingly, while the prior art demonstrates distinct improvements in ET tube capabilities the increasing complexity of these improvements have resulted in a concomitant increase in their cost and reduction in their availability.
Similarly, despite the numerous improvements in the art, anesthetists are still required to insert multiple tubes or catheters into a patient for airway management and patient monitoring purposes. In practice, body core temperature is typically received from a temperature sensor incorporated in a separate esophageal tube. Therefore, in addition to intubating the patient with an ET tube, the anesthetist must also insert a separate esophageal tube. Regardless of insertion order, the insertion of one tube will make the subsequent insertion of the other tube more difficult, particularly when the targets of the respective tubes are incompatible.
The requirements of stocking, maintaining and utilizing multiple devices for a single procedure further contributes to the complexity and cost of the procedures. Similarly, the high cost and complexity of optical and electronic audio guidance mechanisms necessitates that their use be limited to “difficult” airway management cases.
Accordingly, there is a need in the art for reducing the number and complexity of devices required to accurately intubate a patient and effectively monitor patient physiological parameters.